I wanted to put a few short posts up about common errors in thinking. I am not immune to them myself, but knowing what the common errors are seems to help.
One of the more common thinking errors is, "it worked for me". That is, people see someone who is healthy and try to duplicate their particular diet or exercise routine. Unfortunately, this duplication often doesn't work. First, everyone is different. Second, a person may be doing a mix of positive and negative things, but the overall balance is positive. Therefore, if another person just pulls out certain piece's of another's routine, they may get the positive or they may get the negative parts.
Third, even within a healthy framework, like Paleo diet and exercising, there is room for variation. Some people may thrive on more or less meat, or more or less plant food. This doesn't even get into gender differences, which is often overlooked with dietary prescriptions.